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[几何] 动态问题的初中解法(求助)

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力工 Post time 2024-1-11 09:22 |Read mode
如图,已知点$A,B$在半径为$4$的$\odot O$上运动,且$\angle AOB=60\du ,OC=6,BC$的中点为$D$,求线段$AD$长度的取值范围。$[2\sqrt{3}-3,2\sqrt{3}+3]$ QQ图片20240111091534.png
作为初中题,求助如何用平几方法解决?

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爪机专用 Post time 2024-1-11 11:03
换个角度看,将A,B看成定的,C动,就比较容易了
I am majia of kuing

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kuing Post time 2024-1-11 11:09
哦其实直接取 OB 中点 E,则 AE-DE<=AD<=AE+ED 就完了,换不换角度看都无所谓。

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一直只想取OC的中点,就不会换个角度,太鲨了。哈哈  Post time 2024-1-11 13:59

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力工 + 1 正解!这方法妙!

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